Currently, increasing of capacity and improvement of performances are demanded for secondary batteries, specifically lithium ion secondary batteries. Therefore, techniques such as film thickening and increasing of density of electrodes, and introduction of materials having higher Li-storage ability than those of conventional materials, and the like have been developed. However, such film thickening and increasing of density of electrodes, and such batteries using novel materials have a problem of occurrence of a rapid deterioration phenomenon, in which a deterioration reaction gradually progresses inside a battery in accordance with use for a long term, and a side reaction that is different from a general charging and discharging reaction dominantly occurs at a certain timing, and thus an electric capacity that can be taken out is significantly decreased (a rapid deterioration phenomenon in a secondary battery, which is determined as results of both an analysis of voltage responses during application of a constant current and during a rest and an analysis of a current response during application of a constant voltage).
One of the causes thereof is a phenomenon called as reversible Li loss, in which Li released from a positive electrode during charging is not withdrawn into a negative electrode active substance but precipitates as a Li-containing compound or metallic Li, whereby the amount of Li that can be used in a general charging and discharging reaction is decreased (a phenomenon in which the amount of Li that provides and receives electrons by transferring between a positive electrode and a negative electrode decreases). If this reversible Li loss occurs at an accelerated rate, then the charge-discharge efficiency significantly decreases. Therefore, attempts to suppress cycle deterioration by controlling charging and discharging on the basis of a result of presumption of battery states during charging and discharging are made.
One of the above-mentioned attempts is present as a technique of calculating an internal resistance of a secondary battery, and controlling the secondary battery so as to avoid a predetermined deterioration promotion area on the basis of the result of the calculation thereof (see Patent Document 1). Another one of the above-mentioned attempts is present as a technique of defining a negative electrode voltage on a lithium standard electrode to be in a range not greater than 0.6 V, for the purpose of suppressing occurrence of a polarization phenomenon of a negative electrode active substance in which Li is stored associated with discharging (see Patent Document 2).